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25 Coenzyme Q10 (CoQ10) Benefits + Side Effects, Dosage

Written by Aleksa Ristic, MS (Pharmacy) | Last updated:
Jonathan Ritter
Puya Yazdi
Medically reviewed by
Jonathan Ritter, PharmD, PhD (Pharmacology), Puya Yazdi, MD | Written by Aleksa Ristic, MS (Pharmacy) | Last updated:

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Food

CoQ10 is a popular supplement used to boost energy levels, protect the heart, and reduce the side effects of statins. It is important for proper mitochondrial function, heart health, muscle function, and more. Read on to learn the supplementation benefits, dosage, and side effects.

What is Coenzyme Q10?

Coenzyme Q10 (CoQ10) is an important compound found in every cell in the body. It is a type of coenzyme, which means that it helps enzymes work more effectively. CoQ10 is mainly located in the membrane of mitochondria, where it is used to make energy [1].

CoQ10 helps shuttle electrons in the mitochondria to produce ATP, the main form of cellular energy [2].

It is also found in cell membranes and in lipoproteins – such as LDL and HDL – where it acts as a powerful antioxidant. CoQ10 stabilizes cell membranes, helping cells work properly [3].

Energy-demanding organs in your body have the highest levels of CoQ10. These include the brain, heart, kidneys, muscle, and liver – all of which contain many mitochondria and use a lot of energy [1].

Many different diseases and conditions, as well as nutrient deficiencies, can reduce the body’s ability to make CoQ10 or cause CoQ10 to be used up faster than it can be replaced. In these cases, supplementation may be helpful or necessary [4].

CoQ10 is commonly supplemented to help improve diseases that involve mitochondrial dysfunction and increased oxidative stress such as fibromyalgia, chronic fatigue syndrome, and diabetes. Supplementation may also be beneficial for heart diseases, including heart failure [4].

Some people also take CoQ10 supplements to combat the side effects of statins. Athletes, on the other hand, use them to enhance performance [5].

Snapshot

Proponents:

  • Increases energy levels
  • Boosts mitochondrial function
  • Protects against free radicals and inflammation
  • Improves heart health
  • Reduces blood sugar levels and blood pressure
  • Helps with migraines
  • Improves fertility
  • Reduces the side effects of statins and chemo

Skeptics:

  • Poorly absorbed
  • Possible interactions with blood thinners
  • Most benefits lack stronger clinical evidence
  • May not help with Alzheimer’s disease
  • Doesn’t improve exercise performance

Food Sources

The body makes about half of the CoQ10 we need, while we get the rest from food. Excellent sources of CoQ10 include [4, 6, 7]:

  • Meat: beef, chicken, and pork (highest levels in the heart and liver)
  • Fish (herring and sardines, highest levels in the heart)
  • Seafood (shrimp and scallops)

Foods containing much lower CoQ10 levels include [6, 7]:

  • Dairy
  • Eggs
  • Nuts (highest in sesame seeds)
  • Legumes (highest in peanuts)
  • Vegetables (highest in parsley and soybeans)

Ubiquinone vs. Ubiquinol

CoQ10 is mainly found in two forms in the body: ubiquinone and ubiquinol. Ubiquinone is the oxidized version in the body that is recycled (reduced) back into ubiquinol and vice versa. Ubiquinol is primarily responsible for the antioxidant benefits of CoQ10, although ubiquinone may have some antioxidant potential [8, 9].

Ubiquinol makes about 90% – 98% of the CoQ10 in the blood, while ubiquinone makes only a small percentage. Both forms are carried around the body by LDL and HDL. The ratio of ubiquinol to ubiquinone decreases as you age due to poor conversion between the two forms and increased oxidative stress [10, 11, 12, 13].

Antioxidant Effects

CoQ10, in its ubiquinol form, is a strong antioxidant that protects the cell and mitochondrial membranes. But even in its oxidized form as ubiquinone, it may still have some antioxidant effect [1, 9].

The membrane that surrounds cells contains fats that help keep it stable. These fats can become oxidized and damaged, which causes the cell to not work as well. CoQ10 is found within the cell membrane where it acts to prevent this oxidative damage [14].

CoQ10 is carried around the bloodstream by lipoproteins such as LDL and HDL. LDL is especially prone to becoming oxidized, when it becomes more dangerous than regular LDL and may trigger plaque formation and hardening of the arteries. CoQ10 helps prevent LDL from becoming oxidized [15, 16, 3].

Coenzyme Q10 Health Benefits

The following benefits are based on studies that involved supplementation with ubiquinone (the oxidized form of CoQ10). You can learn more about ubiquinol, including its health benefits and dosage, here.

Likely Effective:

1) Coenzyme Q10 Deficiency

In rare cases, coenzyme Q10 deficiency can cause weakness, fatigue, and seizures.

Oral coenzyme Q10 (800 mg daily) seems to improve the symptoms of deficiency in adults. The recommended dosage in children is 30 mg/kg daily in three divided doses [17, 18, 4].

2) Mitochondrial Diseases

Mitochondrial diseases are a group of disorders caused by mitochondria that don’t function correctly. CoQ10 improves symptoms of mitochondrial disorders including poor nerve function, muscular weakness, tremor, inability to exercise, cramps, and muscle stiffness [19, 20, 21, 22, 23].

Possibly Effective:

3) Heart Disease

Hypertrophic cardiomyopathy is a type of heart disease in which the walls of the heart become abnormally thick, causing an irregular heartbeat and making it harder for the heart to pump blood.

Taking 200 mg/day CoQ10 for improved heart function, irregular heartbeat, and quality of life and reduced the heart wall thickness in 87 people with HCM. In another study of 7 HCM patients, 200 mg/day CoQ10 was able to reduce heart wall thickness by 26% [24, 25].

In a 2-year study of 420 people with heart failure, taking 300 mg/day CoQ10 reduced mortality by 43%. A 1-year study found that CoQ10 reduced the number of people who required hospitalization for worsening heart failure. Supplementation also reduced the incidence of fluid buildup in the lungs and asthma [26, 27].

CoQ10 (100 – 320 mg/day) improved exercise capacity in heart failure patients by increasing the ability of the lungs and heart to deliver oxygen to muscles [28, 29].

A review of 14 studies and 2.1K heart failure patients found that CoQ10 reduced mortality by 31% but did not improve heart function or symptoms of heart failure [30].

CoQ10 given within 3 days of a heart attack reduced heart pain, irregular heartbeat, and improved heart function in 144 people. The number of new heart attacks as well as deaths was also reduced in the group taking CoQ10 [31].

CoQ10 improves heart health and may prevent thickening of the heart and heart failure. It also benefits people who have experienced heart attacks and it particularly protective if given within days of experiencing one.

Heart Surgery Outcomes

A review of 8 studies found that CoQ10 taken before heart surgery reduced the need for drugs after surgery and the development of irregular heartbeat [32].

One study found that taking CoQ10 for 14 days before heart surgery helped maintain heart CoQ10 levels, improved heart function, and reduced recovery time [33].

Blood Vessel Health and Circulation

Nitric oxide (NO) is a molecule that helps improve circulation by causing blood vessels to dilate. Healthy blood vessels produce NO to allow proper blood flow and prevent narrowing of the arteries. Free radicals such as superoxide inactivate NO, which prevents blood vessels from dilating and decreases circulation. CoQ10 neutralizes superoxide and increases nitric oxide levels [34, 35, 36, 37].

In multiple studies of over 135 people, CoQ10 (100 – 300 mg/day) improved blood vessel health and increased circulation. CoQ10 supplementation increased levels of superoxide dismutase, an enzyme that neutralizes superoxide [38, 39, 37, 28].

Blood Clotting

Supplementing with 100 mg CoQ10 daily for 20 days reduced the size of platelets and helped prevent them from sticking together [40].

4) Blood Pressure

Multiple studies of over 280 total people with high blood pressure have found that supplementing with CoQ10 (100 – 225 mg/day) reduces blood pressure. Reductions in systolic pressure ranged from 8% to 11% and diastolic pressure ranged from 9% to 12% [41, 42, 43, 44].

In people with slightly high blood pressure, studies have found that CoQ10 reduces systolic pressure 3 – 4% and diastolic 0.4 – 2% [45, 46+].

However, two 12-week studies (40 people with slightly high blood pressure and 30 people with high blood pressure) found no effect from supplementation with 200 mg/day. Another study of 55 people with slightly high blood pressure found no change after 4 months of taking either 600 mg or 1,200 mg daily [39+, 47, 48].

There is good research to suggest CoQ10 reduces blood pressure in people with high blood pressure. People with normal or slightly high levels may see little or no effect.

Pregnancy

Preeclampsia is high blood pressure during pregnancy, with swelling in the hands and feet. Women who took 200 mg/day CoQ10 20 weeks before delivery had a 20% reduced risk of developing preeclampsia (197 total women). Another study of 197 women found a 44% reduced risk of developing preeclampsia [49, 50].

5) Inflammation

CoQ10 reduces levels of inflammatory compounds including CRP and TNF-α. These inflammatory compounds are linked to heart disease and diabetes [51, 52, 53].

In a study of 60 diabetics, CoQ10 reduced levels of the pro-inflammatory cytokine IL-6 [54].

A review of 9 studies and 428 people found that CoQ10 reduced TNF-α, but had no effect on CRP or IL-6 [55].

However, another review of 17 studies and 811 people found that CoQ10 reduced CRP, IL-6, and TNF-α [56].

CoQ10 may reduce inflammation by reducing the production of NF-κB. NF-κB is a protein that controls genes responsible for producing inflammatory compounds [56].

6) Blood Sugar Levels

A meta-analysis of 18 studies and over 700 people found that CoQ10 reduced blood sugar in those with high and normal levels with doses below 200 mg/day and in studies no longer than 12 weeks [57+].

An analysis of 14 studies and 693 overweight and obese people with diabetes found that CoQ10 reduced blood sugar (fasting and HbA1c) and insulin levels in doses below 200 mg/day [58].

One study found no effect on blood sugar in 60 diabetics who supplemented with 120 mg/day for 12 weeks. However, insulin levels decreased. In 23 diabetics, 200 mg/day for 6 months had no effect on blood sugar or insulin sensitivity. In another 8-week study of 80 people with prediabetes, the same dose improved insulin sensitivity without affecting blood sugar levels [59, 60, 61].

In mice with diabetes, CoQ10 reduces blood sugar levels by reducing oxidative stress in insulin-producing cells (beta cells) and increasing antioxidant levels such as superoxide dismutase and glutathione. In cell studies, CoQ10 prevents programmed cell death (apoptosis) in beta cells [62, 63, 64, 65].

On the other hand, it failed to improve insulin and HbA1c levels in most clinical trials. One review found no significant effects on blood glucose, too [66, 57, 67].

In lower doses (200 mg/day or less), CoQ10 may reduce blood sugar levels in people with normal and high levels by improving insulin resistance and protecting beta cells.

7) Diabetes Complications

High blood sugar levels in diabetes damage the nerves, causing pain, tingling, and numbness, known as diabetic neuropathy. In 24 diabetics suffering from neuropathy, 400 mg/day CoQ10 improved nerve function and symptoms of nerve damage [68].

CoQ10 prevented nerve pain and reduced inflammation in diabetic mice [69].

In diabetic mice, CoQ10 prevented nerve pain due to abnormally low blood sugar levels [70].

For example, diabetes can cause brain dysfunction and altered levels of neurotransmitters such as serotonin. CoQ10 reduced oxidative stress and balanced neurotransmitter levels in the brains of diabetic rats [65].

CoQ10 protects the kidneys and heart from high blood sugar levels and improves their function in diabetic rats and mice [71, 72, 73, 74, 75, 76].

8) Infertility

Men

Male fertility is determined by the number (count) and quality (motility and morphology) of the sperm. Sperm cells rely on CoQ10 for the energy needed to move and for its antioxidant protection [77].

A study of 22 men found that taking 60 mg/day for 103 days improved in vitro fertilization rates [77].

A 26-week study of 212 men with infertility found that 300 mg/day of CoQ10 improved sperm count and motility. A slight increase in testosterone was also found [78].

Supplementing with 400 mg/day for 6 months improved motility in 22 men with infertility [79+].

200 mg/day for 12 weeks reduced oxidative stress in 47 infertile men but had no effect sperm count or quality [80].

Women

Poor ovarian reserve (POR) is a term used to describe a reduction in quantity and quality of immature eggs in women of reproductive age. It can reduce the success of in vitro fertilization (IVF).

CoQ10 increased the IVF rate and the number of high-quality embryos in women with this condition, as well as pregnancy and live birth rates [81].

In aging mice, CoQ10 improves the number and health of immature eggs [82].

In higher doses (> 200 mg/day), CoQ10 may boost fertility and sperm quality in men. More studies need to confirm its effects on testosterone levels in men and fertility in women.

9) Migraines

CoQ10 levels are often lower in people who experience migraines [83].

In multiple studies, CoQ10 (100 – 300 mg/day) reduced the duration, frequency, and severity of migraines. In one study, 150 mg/day reduced the number of migraines by over 50% after 3 months [84, 85, 49, 83].

10) Fibromyalgia

Fibromyalgia is characterized by altered CoQ10 distribution in the body and increased oxidative stress. CoQ10 levels may be high in the blood, but low in immune cells. Supplementation can increase CoQ10 levels in immune cells, which protects them and lowers oxidative stress [86].

In multiple studies, CoQ10 supplementation (100 – 300 mg/day) improved symptoms of fatigue, pain, headache, and depression. Supplementation also reduced inflammation and improved mitochondrial function [87, 88, 14, 89+, 90, 91].

11) Muscle Wasting

Muscular dystrophies are a group of genetic disorders that cause muscle wasting, weakness, difficulty breathing, and poor balance.

In two studies of 27 people with muscular dystrophies, 100 mg CoQ10 daily improved their ability to walk and exercise and reduced their fatigue [92].

12) Multiple Sclerosis

In two 12-week studies of 93 people multiple sclerosis, 500 mg/day CoQ10 improved symptoms of fatigue and depression and reduced inflammation [93, 94].

13) Chemotherapy Side Effects

A class of chemotherapy drugs called anthracyclines (doxorubicin, daunorubicin, and aclarubicin) cause damage to the mitochondria of the heart. CoQ10 protects mitochondria in the heart [95, 96].

A review of 6 studies found that CoQ10 protected against damage to the heart and liver during chemotherapy [97].

In a 5-year study of 81 people who had melanoma surgery, those who took CoQ10 (400 mg/day) in addition to the anti-cancer drug were 13 times less likely to have the cancer spread compared to anti-cancer drugs alone. The CoQ10 group also had better mood and energy levels [98].

In rats, CoQ10 protects kidneys from damage due to doxorubicin without interfering with its effectiveness. Mice given CoQ10 lived longer after being exposed to doxorubicin [99, 100, 101, 102].

14) Peyronie’s Disease

Peyronie’s disease (PD) is a disease in which scar tissue builds up in the penis causing curvature, erectile dysfunction, and painful intercourse.

In a clinical trial of 186 people with this disease, 300 mg/day CoQ10 reduced scar tissue, the curvature of the penis, and improved erectile function [103].

Insufficient Evidence:

No valid clinical evidence supports the use of CoQ10 for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.

15) Side Effects of Statin Drugs

Statins block the production of CoQ10 and decrease its levels. One of the most common side effects of statins is damage to the muscles, causing weakness and pain (in 10 – 15% of people). These side effects may be due to low CoQ10 levels and often cause people to quit taking statins [104, 105, 106].

In a study of 50 people taking statins, 100 mg/day CoQ10 reduced muscle pain and improved their ability to accomplish daily activities [106].

In 20 athletes taking statins, 200 mg/day improved muscle strength [107].

Statins can also interfere with the ability of the heart to pump blood. CoQ10 supplementation is able to reverse this and improve heart function in people taking statins [108].

In rats given statins, CoQ10 protects the muscles and liver from damage and improves mitochondrial health [109, 110, 111, 112, 113].

However, in a meta-analysis of six clinical trials, coenzyme Q10 didn’t provide protection against the side effects of statins on muscles [114].

More studies are needed to shed light on these conflicting results.

16) Depression

One study in 18 people with depression found that 400 – 800 mg/day CoQ10 for 4 weeks reduced the severity of the depression and improved symptoms of sadness, fatigue, and difficulty concentrating [115].

Another 8-week study of 69 people with bipolar depression found that taking 200 mg/day CoQ10 improved symptoms of depression including fatigue and difficulty concentrating [116].

Studies in mice reveal that mitochondria don’t function properly in depression. CoQ10 reduces symptoms of depression and stress hormones in rats [117, 118, 119].

Further research is needed to evaluate the antidepressant effects of coenzyme Q10.

17) Parkinson’s Disease

In Parkinson’s disease, dopamine neurons get destroyed. Dopamine is important for movement, learning, and feelings of reward. CoQ10 levels are lower in the mitochondria of people with early Parkinson’s disease [120, 121, 122].

A trial of 80 people with early Parkinson’s disease found that taking either 300 mg, 600 mg, or 1,200 mg daily for 16 months slowed the decline in mental and physical function. The greatest benefit was seen in the group taking 1,200 mg [123].

But in a small trial of 17 people with Parkinson’s, 3,000 mg Coq10 daily for 2 months did not improve mental or physical function compared to placebo [124].

In a mouse model of Parkinson’s disease, CoQ10 protected neurons dopamine-related neurons [125].

In rats with Parkinson’s, CoQ10 in combination with creatine protected the brain and prevented the loss of dopamine that occurs with the disease [126].

Higher doses (> 1,200 mg) of CoQ10 for longer periods may help people with Parkinson’s disease, but more research is needed.

18) Movement Disorders

Friedreich’s ataxia and familial cerebellar ataxia (FCA) are hereditary diseases that result in problems with muscle coordination, movement, speech, and balance. A study of 97 people found that those with Friedreich’s ataxia had 33% lower CoQ10 levels [127].

In a 2-year study of 50 people with Friedreich’s ataxia, CoQ10 (600 mg/day) and vitamin E (2,100 IU/day) improved walking ability, coordination, and speech [128].

A 4-year study of 10 people with Friedreich’s ataxia found that 400 mg/day Coq10 in combination with vitamin E (2,100 IU) improved walking ability and slowed the progression of the disease in 7 people [127].

Six case reports of people with FCA found that doses between 300 mg/day and 3,000 mg/day for one year improved strength and well-being and muscle coordination, and reduced seizure frequency [129, 130].

19) Blood Lipids

CoQ10 reduced total cholesterol and increased HDL cholesterol in people with heart disease, according to a review of 8 studies including over 500 people. However, it had no effect on LDL cholesterol or triglyceride levels [131].

On the other hand, according to another review of 21 studies and 1k people, CoQ10 does reduce triglyceride levels in people with metabolic disorders but has no effect on total, LDL, or HDL cholesterol levels [132].

CoQ10 may improve cholesterol levels in people with heart disease and triglyceride levels in people with metabolic disorders. More research is needed.

20) Gum Inflammation

CoQ10 reduced gum inflammation in 30 people with gum disease [133].

When applied directly to the gums, CoQ10 improved gum health and reduced bleeding [134].

21) Dry Mouth

Dry mouth is thought to be caused in part by reduced ATP saliva production. Supplementing with CoQ10 increased saliva production in a study of 66 people with dry mouth [135].

22) Lung Diseases

People with chronic obstructive pulmonary disease (COPD) have difficulty breathing and lower CoQ10 levels than healthy people. In an 8-week study, CoQ10 increased oxygen in the blood, decreased heart rate during exercise, and improved exercise performance in 21 people with COPD [136].

In 41 people with bronchial asthma, a combination of CoQ10, vitamin E, and vitamin C reduced the dosage of drugs (corticosteroids) needed [137].

23) Skin Protection

UV radiation from the sun causes free radical damage in the skin, leading to wrinkles. CoQ10 applied to skin decreases free radicals and inflammation and increases antioxidant levels. It also reduces the depth of wrinkles and decreases oxidative stress and DNA damage due to UV radiation [138, 139, 140, 141].

24) Aging

A trial of 443 elderly people, selenium (200 mcg) and CoQ10 (200 mg/day) over a 4-year period improved vitality, physical performance, and quality of life [142].

There’s not enough evidence to say if CoQ10 can increase lifespan, although scientists are investigating the possibility.

One study in humans found that levels in multiple organs including the heart, liver, and kidneys all peaked before the age of 20 and decreased with age [143].

In a study of adults aged 18 to 82 years, levels were lowest in the older adults. Another study found that young children had lower CoQ10 levels than adults aged 28 – 78 years [144, 145].

In a study of people aged 22 – 100, levels were lowest in those aged 90 – 100 years. However, CoQ10 levels were not associated with age but instead with levels of lean muscle mass. In older adults, physical activity was linked to higher CoQ10 levels while in younger adults, activity was associated with lower CoQ10 levels [146, 147].

CoQ10 increases the lifespan of rats, bees, and worms. On the other hand, mice deficient in CoQ10 live shorter lives. However, other studies in mice and rats have found no effect on lifespan [148, 149, 150].

25) Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a liver disorder that involves chronic inflammation. Taking 100 mg decreased liver enzymes (AST and GGT) and markers of inflammation in a 12-week study of 41 people with this disorder [51].

In rats exposed to toxins, CoQ10 reduces liver enzymes, inflammation, and damage and increases antioxidant levels in the liver [151, 152, 153, 154].

Animal and Cellular Research (Lacking Evidence)

No clinical evidence supports the use of CoQ10 for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based research, which should guide further investigational efforts. However, the studies listed below should not be interpreted as supportive of any health benefit.

Gut Health

In rats, CoQ10 prevented damage to the gut from alcohol [155].

Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen can cause damage to the gut. CoQ10 reduced gut damage by increased antioxidant levels and boosting levels of gut-protective prostaglandin E2 [156, 157].

In a rat model of ulcerative colitis (UC), CoQ10 improved gut health by reducing oxidative stress and inflammation [158].

Bone Loss (Osteoporosis)

Osteoporosis is a disease in which bones become weak and brittle due to bone loss. CoQ10 reduces the breakdown of bone and increases new bone formation in rats with osteoporosis [159, 160, 161, 162].

Cancer

In rats, CoQ10 reduced the growth of tumors in the colon and blocked the development of precancerous lesions [163].

CoQ10 increased oxidative stress and reduced cell growth in cancer cells without affecting normal cells. CoQ10 prevented cell growth and caused programmed cell death in cervical cancer cells. Still, this doesn’t tell us about the actual anticancer effects in living organisms [164, 165].

Clinical trials are needed to investigate the potential anticancer effects of coenzyme Q10. At this point, it can not be recommended for cancer prevention or treatment.

Possibly Ineffective:

Alzheimer’s Disease

Alzheimer’s disease is characterized by beta-amyloid plaques and tau proteins in the brain. In mice with Alzheimer’s disease, CoQ10 reduces oxidative stress, beta-amyloid plaques, and tau proteins in the brain. However, a clinical trial in 78 patients with Alzheimer’s disease found that ubiquinol did not improve markers of disease activity or oxidative stress [166, 167, 168, 169].

Likely Ineffective:

Exercise-Related Fatigue and Performance

A study of 17 people found that those taking 300 mg/day CoQ10 for 1 week were able to pedal faster during a bicycle workout and felt less tired after [170].

However, 150 mg daily did not increase energy output in 6 physically-active people after 4 weeks [171].

In another study of 18 cyclists and triathletes, 1 mg/kg (0.45 mg/lb) CoQ10 daily for 28 days had no effect on athletic performance [172].

Additionally, in a study of seven triathletes, 100 CoQ10 with 600 mg vitamin C and 270 mg vitamin E did not affect fatigue or performance during cycling exercise [173].

200 mg/day for 12 weeks did not affect exercise performance in chronic kidney disease patients either [174].

Huntington’s Disease

Huntington’s disease is a genetic disorder that causes physical and mental problems early in life. Mitochondria in the brains of people with Huntington’s become damaged and don’t work as well they should [175].

A study of 347 people with Huntington’s disease found that taking 600 mg/day for 2.5 years slightly improved mental function and ability to handle day-to-day tasks. However, the results did not reach significance [176].

In a large high-quality trial of 609 patients, coenzyme Q10 (2.4 grams daily for up to 5 years) did not slow the functional decline in patients with Huntington’s disease [177].

Coenzyme Q10 Safety & Precautions

Side Effects

This list does not cover all possible side effects. Contact your doctor or pharmacist if you notice any other side effects. In the US, you may report side effects to the FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada, you may report side effects to Health Canada at 1-866-234-2345.

CoQ10 is generally very well-tolerated, even at the high doses. Side effects are mild and include [178]:

  • Upset stomach
  • Diarrhea
  • Nausea
  • Loss of appetite
  • Headache
  • Rash

CoQ10 is processed by the liver and is eliminated through bile. This means people with poor liver function or blocked bile ducts who supplement with CoQ10 may accumulate high levels in their body, increasing the risk of side effects [178].

Drug Interactions

Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let them know about all drugs and supplements you are using or considering.

Warfarin (Coumadin)

CoQ10 is structurally similar to vitamin K, which has blood-clotting effects and can interfere with the effectiveness of warfarin [1, 179].

There have been multiple case reports of CoQ10 reducing the effectiveness of warfarin [180, 181, 182].

Blood Pressure-Lowering Drugs

CoQ10 can reduce blood pressure. The combination with blood pressure-lowering drugs may lead to very low blood pressure [41, 42, 43, 44].

Blood Sugar-Lowering Drugs

CoQ10 can reduce blood sugar levels. The combination with blood sugar-lowering drugs may further lower blood sugar [57, 58].

Theophylline (Elixophylline, Theochron)

CoQ10 increased the time it took the drug theophylline (used to treat asthma and COPD) to reach peak blood levels in rats. People taking theophylline should consult their doctor before supplementing with CoQ10 [183].

Coenzyme Q10 Dosage & Supplement Forms

Dosage

The below doses may not apply to you personally. If your doctor suggests using CoQ10, work with them to find the optimal dosage according to your health condition and other factors.

CoQ10 supplements come in two forms: ubiquinone and ubiquinol. If the supplement label only has “CoQ10” on it, then it is most likely ubiquinone.

For most of the studied diseases and conditions, 100 – 300 mg of ubiquinone divided into two daily doses is effective. Higher doses may be needed to see improvement in neurodegenerative diseases [56, 14, 39, 26, 43, 128+, 130+, 123].

Taking a dosage of 1,200 mg of ubiquinone daily is safe long-term. Up to 3,000 mg daily may be safe in the short-term (up to 2 weeks). However, doses above 2,400 mg/day do not result in any further increase in blood CoQ10 levels [123, 130, 124, 184].

Synergies

CoQ10 is fat-soluble, meaning it is best absorbed when taken with a meal that contains oils or fats. CoQ10 formulations that are mixed with oil are absorbed better than powders and pills. Taking vitamin C and vitamin E at the same time as CoQ10 may reduce its absorption [1, 185, 186].

Even when it is consumed with a fatty meal, CoQ10 is still poorly absorbed. Absorption also varies greatly between people due to differences in gut bacteria and the ability to absorb fats [187, 186].

CoQ10 is often combined with vitamin E to enhance its antioxidant effects [1].

User Reviews

The opinions expressed in this section are solely from the users who may or may not have a medical background. SelfHacked does not endorse any specific product, service, or treatment. Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice because of something you have read on SelfHacked.

People who supplement with CoQ10 generally report increased mental and physical energy levels as well as improved strength and stamina. Fibromyalgia patients report decreased pain in addition to improved energy and mental clarity. Some users do report fatigue and brain fog when taking it.

Takeaway

CoQ10 is vitally important to maintaining energy levels and preventing oxidative stress throughout the body, especially in the heart. Low levels of CoQ10 can be caused by various diseases, conditions, nutrient deficiencies, and statin drugs.

CoQ10 supplementation may help with heart disease, fibromyalgia, high blood pressure, mitochondrial dysfunction, migraines, and more. The evidence is weaker for depression, Parkinson’s disease, aging, and cholesterol levels.

CoQ10 is safe and only has mild side effects, but it can reduce the effectiveness of blood-thinners. Absorption of CoQ10 is poor, so it should be supplemented with a high-fat meal. Up to 1,200 mg/day is safe for long-term supplementation.

About the Author

Aleksa Ristic

Aleksa Ristic

MS (Pharmacy)
Aleksa received his MS in Pharmacy from the University of Belgrade, his master thesis focusing on protein sources in plant-based diets. 
Aleksa is passionate about herbal pharmacy, nutrition, and functional medicine. He found a way to merge his two biggest passions—writing and health—and use them for noble purposes. His mission is to bridge the gap between science and everyday life, helping readers improve their health and feel better.

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